SPC Day 2 Thunderstorm Outlook Issued 0830Z 20040127

ZCZC SPCSWODY2 ALL
ACUS02 KWNS 270746
SPC AC 270746
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0146 AM CST TUE JAN 27 2004
VALID 281200Z - 291200Z.
...NO TSTM AREAS FORECAST...
...SYNOPSIS...
A PROGRESSIVE SPLIT FLOW PATTERN WILL PREVAIL OVER THE LOWER 48 ON
WEDNESDAY...WITH MAIN POLAR JET EXTENDING FROM BC ACROSS THE NRN
PLNS TO THE MID ATLANTIC/NEW ENGLAND CST. FARTHER S...EXPECT A
WEAKER SRN BRANCH TO EXTEND FROM CA SEWD ACROSS AZ/NRN MEXICO...AND
THEN E ACROSS S TX TO THE CNTRL GULF CST.
THE LARGE SCALE PATTERN WILL BE A BIT MORE ZONAL THAN IN RECENT
DAYS. BUT SOME AMPLIFICATION DOES APPEAR LIKELY...ESPECIALLY LATER
IN THE PERIOD OVER THE WRN U.S. AS HEIGHTS RISE OVER THE E PACIFIC.
THIS SHOULD ALLOW SHORTWAVE IMPULSE NOW APPROACHING THE ORE/NRN CA
CST TO TRACK SEWD...WITH THE SYSTEM REACHING SRN CA/NV BY 12Z
WEDNESDAY... AND NRN SONORA/CHIHUAHUA BY 12Z THURSDAY.
THE GFS AND ECMWF ARE IN MUCH BETTER AGREEMENT THAN YESTERDAY
REGARDING THE CA/NV SYSTEM...WITH THE COMPROMISE SOLUTION NOW BEING
FORECAST CLOSER TO THAT OF THE SLOWER/STRONGER ECMWF.
...S TX...
THE LOW LEVEL FLOW SHOULD VEER TO SELY ACROSS S TX ON WEDNESDAY AS
CA/NV UPPER IMPULSE REACHES NRN MEXICO. WHILE THIS WILL ALLOW FOR
MODEST BOUNDARY LAYER AIR MASS RECOVERY...SIGNIFICANT BOUNDARY LAYER
MOISTURE RETURN WILL LIKELY NOT OCCUR UNTIL AFTER 12Z THURSDAY AS
OFFSHORE COASTAL TROUGH FINALLY WEAKENS. AT THE SAME TIME...SOME
WARMING/STRENGTHENING OF EXISTING CAP CAN BE EXPECTED IN THE 800 TO
700 MB LAYER AS UPPER SYSTEM APPROACHES FROM THE WEST. GIVEN THE
ABOVE THERMODYNAMIC SETUP AND THE ABSENCE OF STRONG MESOSCALE
FORCING FOR ASCENT...THE PROSPECTS FOR THUNDERSTORM DEVELOPMENT OVER
LAND APPEAR MINIMAL. SOME STORMS MAY DEVELOP IN RESPONSE TO
PERSISTENT LOW LEVEL WARM ADVECTION INVOF WEAKENING COASTAL TROUGH
LATE IN THE PERIOD...BUT THESE SHOULD REMAIN OFFSHORE.
..CORFIDI.. 01/27/2004
...NOTICE...
FOR USERS DECODING THE POINTS PARAGRAPH HEREIN...LATITUDE AND
LONGITUDE POINTS FOR THE CATEGORICAL AND PROBABILISTIC OUTLOOK
GRAPHICS ALSO ARE LOCATED IN A SEPARATE PRODUCT UNDER THE WMO
HEADINGS WUUS01 PTSDY1...WUUS02 PTSDY2...AND WUUS03 PTSDY3. THE
INCLUSION OF POINTS IN THIS PRODUCT WILL EVENTUALLY BE DISCONTINUED.
$$